Electrical energy plays a central role in industrialized societies. The reliability of electric power systems is a critical factor in the planning, design and operation of power distribution systems. To ensure reliability, automated, real-time control of the system is desirable to allow for rapid response to the actual demand of electricity and any unforeseen contingencies such as equipment outages.
Modernized power distribution networks typically utilize energy control centers to monitor and regulate network operation. Although these centers have greatly advanced in technology, their basic control objectives of economy and security remain the same. The economic goal is to minimize the cost of supplying the electrical demand. The security goal is directed to the minimum requirements for reliability and quality of service. Electric utilities desire measurements of line voltage and current to allow for automated customer billing, load and reliability monitoring, and for real time control of the system.
The power distribution industry is increasingly relying on automated systems for providing real time control over the power distribution system. Remote monitoring and switching equipment is increasingly being relied on to monitor and control the power distribution system. Many segments of the power distribution system are underground such as underground vaults or chambers. Some segments of the power distribution system are accessed in above ground compartments or ‘pad mounted’ systems.
The power distribution system is composed of many high voltage segments that deliver electricity to local homes and businesses. Monitoring and controlling these high voltage segments of the system in underground vaults or pad mounted compartments poses the problem of finding a lower voltage power supply for the switching and monitoring equipment. The switches and monitoring equipment typically run on low voltage direct current power supplies. This type of power supply is not typically available in the underground vaults or pad mounted compartments where the high voltage lines run. A standard transformer to convert the high voltage into a lower voltage for this equipment is large, expensive and time consuming to install, requiring modification of the existing high voltage lines and possibly of the underground vault or pad mounted compartment.